"Coanda Effect"

Discussion in 'Powerboats' started by yipster, Apr 3, 2004.

  1. yipster
    Joined: Oct 2002
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    yipster designer

  2. Corpus Skipper
    Joined: Oct 2003
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    Corpus Skipper Hopeless Boataholic

    Cool! But no efficiency numbers. :(
  3. gonzo
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    gonzo Senior Member

    Do they claim a boat propulsed by this dive creates no wake? It is a jet drive with a very short nozzle and completely submerged. The thrust is created by the acceleration of water mass. The pressure on the after body has no effect on thrust. There is an equal amount of pressure on the housing and the "after body", which cancel out.
  4. ClarkT
    Joined: Jun 2003
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    ClarkT Senior Member


    I don't know about this 'no wake' business, but I can tell you the Coanda effect is for real, and can produce some impressive forces. I worked on a research project in school where we used the Coanda effect on a Kort nozzle to create steering forces. There were no moving external parts (except the propeller). A pump pushed water into the stream near the trailing edge of the Kort nozzle. Depending on whether it is pushed on the 'inside' or 'outside' of the Kort nozzle made a huge difference in the aft separation point or the flow on that side of the nozzle. This made for some strong side forces.

    Very cool technology, just waiting for the right application.

  5. yipster
    Joined: Oct 2002
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    Location: netherlands

    yipster designer

    thanks for the insights. on efficiency:: "A vacuum cleaner, developed specifically to exploit the Coanda effect, will consume less power, have a smaller diameter fan, weigh half as less and have a fan efficiency seven times greater than a conventional cleaner." impressive!

    in a bit deeper dive into this effect i realised its a bigger fenomen than i thought. read forexample the computer fluid dynamics review. also crossed the new zealand pulsejet entusiast again who wants to use the effect in his new X-jet engine. tesla's / coanda turbine theory's and more alternativ the malmo group is building Counda flying sourcers (as did avro for the usa gov). the links on this page i found very interesting, about kelvins thunderstorm experiment to trouthy's scalar electromagnetics and overunity electrical systems. yum yum, before you know it you be lost in time!

    Counda is named together with bernouli and reynolds and the effect is and can be used in many applications.
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